The present invention is directed to acoustic composites or laminates useful in sound control. It finds particular application in conjunction with water deflectors, however, it will be appreciated that the invention finds utility in conjunction with all manner of sound control and/or moisture or environmental shielding.
Open-cell foams have proven useful in sound control. Acoustic energy enters the open-cell passages where it is trapped and absorbed. However, in a wet or hostile environment, the open cells become passages for water and other contaminants to penetrate the foam.
Water shields, deflectors, or protectors are commonly used in the automotive industry to protect inner door trim panels, as well as components mounted thereon, from being damaged by water entering the interior of the doors. Vehicle manufacturers have also been interested in achieving sound insulation through the use of such deflectors. One type of water deflector which has been in use for some time comprises a layer of closed cell polyethylene foam interposed between thin layers of polyethylene film. This sheet construction can be processed using standard techniques and performs satisfactorily in its water deflecting function; however, it does not contribute significantly in terms of sound insulating qualities.
While various material combinations have been proposed for use as sound insulating water deflectors, these combinations have typically had significant drawbacks in terms of cost and/or processing difficulties. For example, it is often desirable to provide the deflectors with variable thicknesses, e.g., having an increased thickness in regions where sound control is needed most and decreased thickness where assembly considerations require it. One technique is to compress the part with the application of heat and pressure to compact the foam in specific or predetermined areas. This technique has a number of drawbacks. The heat and pressure process is slow and expensive. Also, the foam in the compressed areas is still present and can cause problems such as wicking of water, particularly if the article is mispositioned during application. Furthermore, the compressed foam is opaque which creates assembly and handling problems. For example, the opacity makes it difficult to locate screws or other fasteners which must pass through the water deflector. The opacity also makes it difficult to verify adequacy of seal pressurization.
The present invention contemplates a new and improved sound-insulating water shield or deflector which overcomes the above-referenced problems and others.